Polymer electrolyte, a polymer aggregating agent prepared therefrom, and a disposal of waste water

ABSTRACT

A polymer electrolyte which contains an inorganic pigment, having a sulfonated polystyrene resin as a principal ingredient, and is soluble to water.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a polymer electrolyte which includes asulfonated polystyrene resin, further to a polymer aggregating agent anda disposal of waste water.

2. Description of Prior Art

The polystyrene resin is transparent, and is excellent in electricproperties, rigidity, and resistance to water. In addition, it requiresless cost for production. Accordingly, the polystyrene resin is usedalone, or as copolymers and alloys in combination with other resins toserve as a material of buffering members (foamed styrol), packingmaterials, or cabinets and parts of electric appliances and automobiles,and has been used as widely as polyolefin resins represented bypolyethylene.

The polystyrene resin is used not only as a structural element asdescribed above, but can be used, for example, as an agglutinating agentafter it has been converted to a polymer electrolyte.

Recently, a world-wide attention has been directed to protection ofnatural environment, and preservation of clean water resources isthought as a key to the problem. Under these circumstances, legalregulations controlling liquid waste discharged from plants and generalhouseholds as are specified in the sewage control law become morestrict.

To control waste water, recourse has been made to purification by avariety of polymer aggregating agents. The polymer aggregating agentwidely used includes non-ionic/anion types for industrial water wastes,and cationic types for general sewage and human excretions. Althoughthese aggregating agents are chosen as appropriate according to a givenapplication, they are required of, in common, having properties to cleanliquid waste, concentrate it and remove water content from it. Of theseproperties, the cleaning activity of a suspension is most important, anddemand for that activity has been increasingly strengthened from theviewpoint to protect environment from pollution because the filtrateproduced after sewage has been treated with an aggregating agentsdischarged into rivers, lakes and the sea in local areas.

Under these circumstances, trials have been made in which two kinds ofpolymer aggregating agents are combined or a polymer aggregating agentis combined with a metal compound, to give a product capable of reducingthe chemical oxygen demand (COD) and turbidity of a filtrate.

However, conventional technologies have not produced yet any aggregatingagents that can satisfactorily clean a suspension, and improvement ofconventional technologies involved in water treatment has been desired.

OBJECTS AND SUMMARY OF THE INVENTION

This invention intends to provide a polymer electrolyte which dissolvessufficiently readily into water.

In addition, this invention intends to provide a polymer aggregatingagent which is highly potent in purifying a suspension, and to providefurther a liquid waste disposal which is highly effective for thepurification of a suspension.

Furthermore, this invention intends to provide a polymer aggregatingagent which is highly potent in purifying a suspension and can reducethe water content of produced cakes.

The polymer electrolyte of this invention contains a sulfonatedpolystyrene resin as a principal ingredient, in addition to an inorganicpigment, and is water soluble.

The presence of the inorganic pigment, during sulfonation of thepolystyrene resin, inhibits cross-linking reactions, thereby suppressinggelation of the product. Through this maneuver, unnecessary polymers arenot generated in water, and water-soluble polymer electrolytes can bestably obtained.

The polymer aggregating agent of this invention contains a polymercompound as a principal ingredient, and, in addition, carbon black. Theliquid waste disposal this invention provides consists of adding thepolymer aggregating agent to liquid waste, aggregating suspendedmatters, and removing the aggregated matters by filtration.

Use of a polymer aggregating agent supplemented with carbon black or useof a polymer aggregating agent together with carbon black will enhancethe purification activity of that agent towards a suspension.

The polymer aggregating agent of this invention contains a sulfonatedstyrene polymer as a principal ingredient and has a molecular weight of150,000-600,000.

Use of a styrene polymer having a comparatively large molecular weightwill enhance the purification activity of the product towards asuspension, and reduce the water content of resulting cakes.

The polymer electrolyte of this invention contains, in addition to aninorganic pigment, a sulfonated polystyrene resin as a principalingredient, and is water soluble.

The inorganic pigment may include either carbon black or titanium oxide,or both, and the content may be 1×10⁻⁵ -15 wt %, or more preferably5×10⁻⁴ -5 wt %.

Carbon black and titanium oxide can be chosen from any general productsthat are used as a colorant of resins, a reinforcing agent or an agentconferring electroconductivity. For example, carbon black can be chosenfrom any products that have been produced by a channel method, furnacemethod or thermal method.

A carbon black product which has been produced by any one of thosemethods may be used, or carbon black products which have been producedby different methods may be used in combination. It preferably has anaverage particle size of 5-500 nm, or more preferably 10-50 nm. Titaniumoxide may have a rutile, anatase, or ultra-fine structure. Titaniumoxide with any one structure may be used or titanium oxide crystals withdifferent structures may be used in combination. It preferably has anaverage particle size of 0.01-50 nm, or more preferably 0.05-10 nm.

The polystyrene resin may consist of a single polystyrene compound, or acopolymer of a styrene with other monomers. When the polystyrene resinconsists of a copolymer, the styrene unit preferably occupies 30 mol %or more. The polystyrene resin may be alloys or blends which resultafter the styrene unit has been combined with other polymers. In thiscase, the polystyrene resin preferably occupies 20 wt % or more of thetotal product.

The styrene copolymer may include styrene-butadiene,styrene-acrylonitrile, styrene-butadiene-acrylonitrile,styrene-(metha)acrylate (aliphatic hydrocarbons with 1-4 carbons),styrene-acrylonitrile-(metha)-acrylate esters (aliphatic hydrocarbonswith 1-4 carbons), styrene-butadiene-(metha) acrylate ester (aliphatichydrocarbons with 1-4 carbons), styrene-anhydrous maleate, andstyrene-an hydrous itaconic acid. Of them preferred arestyrene-butadiene, styrene-acrylonitrile,styrene-butadiene-acrylonitrile, styrene-acrylonitrile-(metha)acrylateesters (aliphatic hydrocarbons with 1-4 carbons), and styrene-butadiene-(metha)-acrylate esters (aliphatic hydrocarbons with 1-4 carbons), andstyrene-a nhydrous maleate. Of them, styrene-butadiene,styrene-acrylonitrile, styrene-butadiene-acrylonitrile, andstyrene-anhydrous maleate are particularly preferred. These styrenecopolymers may be used alone or in combination with polystyrene or otherstyrene copolymers. The polystyrene resin preferably has a molecularweight of 5,000-10,000,000, more preferably 50,000-100,000, or furthermore preferably 100,000-500,000.

When the polystyrene resin is made into an alloy, or used as a blend,other polymers to be combined with the alloy or blend may includepolyphenylene ether, polycarbonate, polyphenylene sulfide, polyamide(nylon), polyethyleneterephthalate, and polybutyleneterephthalate. Ofthem particularly preferred are polyphenylene ether and polycarbonate.Any one of them may be used alone, or two or more of them may be used incombination.

The above-described polymer electrolytes can be used as an aggregatingagent for the treatment of liquid waste, dispersant for cementproduction, thinning agent for paper production, electroconductive agentfor copying machines, and anti-static electricity agent. They areparticularly well suited for the treatment of liquid waste, dispersal ofcement particles, thinning of paper fibers and electroconduction of thetoner particles of copying machines.

The manufacture of the polymer electrolyte of this invention is toproduce the polymer electrolytes as described above, and consists ofconverting a polystyrene resin into a water-soluble polymer electrolyteby sulfonating the resin in the presence of an inorganic pigment.

The polystyrene resin may be chosen from among those described above,and can be also adopted from a new material (virgin material) speciallyprepared for the production of the polymer electrolyte of thisinvention, or from wastes (waste materials) from plants, shops andhouseholds. Or, a combination of virgin and waste materials may be used.As seen from above, this invention can recycle polystyrene resins whichhave been mass-produced as a general-purposes in and wasted, and henceis very beneficial for the protection of global environment fromartificial pollutants. From this point of view, it is desirable for thisinvention to adopt waste materials as a source of polystyrene resinsrather than virgin materials. As a source of polystyrene resins, it isdesirable to resort to wastes from plants and shops than those fromgeneral households, because the wastes from plants and shops may be moreor less homogenous in composition.

Prior to sulfonation, the polystyrene resin is dissolved in an organicsolvent, or dispersed there, to which is added a sulfonating agent. Whena polystyrene resin is used in combination with another polymer, the twocompounds are dissolved or dispersed in an organic solvent.

The organic solvent preferably includes halogenated aliphatichydrocarbons with 1-2 carbons, particularly 1,2-dichloromethane,chloroform, dichloromethane, and 1,1-dichloroethane. To this organicsolvent is preferably added the polystyrene resin at 0.5-50 wt %, ormore preferably 2-20 wt %, though the addition is more or less dependenton the molecular weight of the resin.

Saturated or unsaturated cyclic hydrocarbon compounds may be used. Thesaturated cyclic hydrocarbon compound may include cyclopenthane,methylcyclopenthane, cyclohexane, methylcyclohexane, ethylcyclohexane,p-menthane, bicyclohexyl, dekalin, sabinane, etc. The unsaturated cyclichydrocarbon compound may include cyclohexane, monocyclic monoterpene(limonene, sylvestrene, and terpinene), dicyclic monoterpene (carene,pinene, sabinene, and camphene), and terpinorene. Of these cyclichydrocarbons, saturated cyclic hydrocarbons are more preferred.

The solvent which can coexist with such a cyclic hydrocarbon mayinclude, in addition to above-described aliphatic hydrocarbons, paraffinhydrocarbons with 1-7 carbons, acetonitrile, carbondisulfide,tetrahydroflan, tetrahydrobilan, acetone, methylethylketone, thiophene,etc. Of them particularly preferred are paraffin hydrocarbons,acetonitrile, tetrahydroflan, and acetone.

The sulfonating agent may include anhydrous sulfuric acid, fumingsulfuric acid, chlorosulfonic acid, and concentrated sulfuric acid. Theaddition of the sulfonating agent is preferably set to 0.5-2.0 mol forevery benzenering in the branched chain of the polystyrene resin, orpreferably 0.7-1.5 mol. When a polyphenylene ether or polycarbonateresin is used in combination, benzene rings in the backbone of thisresin and benzene rings in the above-described polystyrene resin shouldbe taken into account, to determine the amount of the sulfonating agentto be added. If addition of the sulfonating agent is too little, theproduct would be insufficiently sulfonated and its solubility to waterwould be also insufficient. On the contrary, if addition of thesulfonating agent is too much, cross-linking reactions within and amongmolecules would be enhanced, which would lead to increased production ofby-products, and solubility of the product to water would be alsoimpaired.

The sulfonating agent may be used in combination with a Lewis base. Inthis case, the Lewis base may include alkyl phosphates such astriethylphosphate and trimethylphosphate, dioxane, anhydrous aceticacid, ethyl acetate, diethylether, thioxane, etc.

The sulfonating reaction preferably takes place at 0-80° C., or morepreferably at 10-60° C.

It is important to allow either carbon black or titanium oxide or aninorganic pigment to coexist during the sulfonation. During thesulfonation, either carbon black or titanium oxide, or both arepreferably allowed to exist at a concentration of 1×10⁻⁵ -25 wt %, ormore preferably at 5×10⁻⁴ -10 wt %.

The inorganic pigment may be added to the reaction system prior tosulfonation so that it can coexist during sulfonation occurringsubsequently, or inorganic pigment remains in the polystyrene resin maybe used instead. Typically, polystyrene resin waste contains carbonblack or titanium oxide as an additive, and when the content satisfiesthe above-described requirement, the polystyrene resin waste can undergosulfonation without any deliberate addition of an inorganic pigment. Theresin supplemented previously with an inorganic pigment disperses morereadily in a reaction system. The resin supplemented with an inorganicpigment in advance preferably contains the pigment at 0.002-50 wt %,particularly at 0.01-10 wt %.

When an inorganic pigment is allowed to coexist during the sulfonationof a polystyrene resin as described above, it improves thedispersibility of the resin so that reaction proceeds evenly. Thisinhibits cross-linking reactions within and among involved molecules,thereby suppressing the production of by-products insoluble to water.Thus, presence of an inorganic pigment in the reaction system ensuresstable production of water-soluble polymer electrolytes, improves thedispersibility of polymer electrolytes, and allows stable production ofpolymer electrolytes even in quality.

The reaction system, after sulfonation as described above, is allowed toreact with a basic compound to be neutralized. The basic compound mayinclude hydroxides and carbonates of alkali metals and alkali earthmetals, ammonia, and primary to tertiary alkyl amine compounds. It maybe added neat or as a solution gradually until the system is completelyneutralized. When it is added as an aqueous solution, its additionvaries according to the molecular weight of the polystyrene resin, butpreferably is 1-100 times, or more preferably 2-50 times the totalweight of the resin. When the neutralization reaction is completed, thesolvent may be removed by fractional distillation or evaporation.

Above procedures produce a water-soluble polymer electrolyte containingan inorganic pigment. Although generally the polymer electrolytecontaining an inorganic pigment is excellent in its homogenousdispersibility when dissolved in water, it may be removed of theinorganic pigment by filtration as needed.

In addition, this invention enables disposal of liquid waste byutilizing the polymer electrolyte containing carbon black as anaggregating agent, or by utilizing the polymer aggregating agent incombination with carbon black.

Carbon black to be used in this invention may include the productsgenerally used as a coloring agent or a reinforcing agent of resins, oras a conductivity-conferring agent. Carbon black can be chosen from anyproducts that have been produced by a channel method, furnace method orthermal method. A carbon black product which has been produced by anyone of those methods may be used alone, or carbon black products whichhave been produced by different methods may be used in combination. Itpreferably has an average particle size of 5-500 nm, or more preferably10-50 nm.

When carbon black is placed in waste water, minute particles and organicelements suspending in the water cluster together around carbon blackparticles as nuclei, to form aggregates. These tiny aggregates, thanksto the polymer aggregating agent, cluster further together to formlarger aggregates, which are then removed by filtration. This willresult in reduction of the turbidity and COD of the filtrate.

In above procedure, whether carbon black is added after having beencombined with the polymer aggregating agent, or it is addedindependently of the polymer aggregating agent, the resulting effectwill be the same. However, it is preferable for carbon black to becombined with the polymer aggregating agent prior to use, because thenthe polymer aggregating agent will disperse more evenly in waste water,and require no complicated processes as would be necessary if theseagents were added separately.

If they are added separately, any one of the two may come first, but itis more preferable to add carbon black first.

When carbon black is combined with the polymer aggregating agent, itsaddition is preferably set to 0.01-20 wt %, or more preferably 0.05-10wt % with respect to the polymer content of the polymer aggregatingagent. When carbon black is added independently of the polymeraggregating agent to waste water, its added amount is typically0.005-1000 ppm, or preferably 0.01-200 ppm, although the amount may beadjusted more or less according to the concentration of suspendedparticles (SS) in the water. If the added amount is too little, thefiltrate, even after being removed of aggregates, will still hold aconsiderable fraction of turbidity and COD. On the contrary, if theadded amount is too much, carbon black will remain in the filtrate, orinterfere with aggregation of suspended particles.

The polymer compound constituting the polymer aggregating agent mayinclude sulfonates of polystyrene resins, non-ionic or anionicacrylamide resins, or cationic resins. They may be used alone or incombination. Non-ionic, anionic and cationic polymer aggregating agentsappropriate for this invention will be given for illustration.

<Non-Ionic Polymer Aggregating Agents>

They may include polyacrylamide and polymethacrylamide, and preferablypolyacrylamide.

<Anionic Polymer Aggregating Agents>

They may include (metha)acrylate resins such as polyacrylamide andpolymethacrylamide having undergone partial hydrolysis, copolymers of anacrylic acid or methacrylic acid with acrylamide or methacrylamide, ortheir salts, and triple copolymers of an acrylic acid or methacrylicacid with acrylamide or methacrylamide, and 2-acrylamide-methylpropanesulfonic acid or vinylsulfonic acid, and their salts.

Preferred are polyacrylamide having undergone partial hydrolysis,copolymers of an acrylic acid with acrylamide and their salts, andtriple copolymers of an acrylic acid with acrylamide and2-acrylamide-methylpropane sulfonic acid, and their salts.

The polystyrene sulfonate polymer may include polystyrene,styrenebutadiene, styrene-acrylonitrile,styrene-butadiene-acrylonitrile, styrene-(metha)acrylate,styrene-(metha)acrylate ester (aliphatic hydrocarbons with 1-4 carbons),styrene-butadiene-(metha)acrylate ester (aliphatic hydrocarbons with 1-4carbons), styrene-anhydrous maleic acid, and styrene-anhydrous itaconicacid.

The polystyrene sulfonate polymer may include polystyrene,styrene-butadiene, styrene-acrylonitrile,styrene-butadiene-acrylonitrile, styrene-(metha)acrylate,styrene-(metha)acrylate esters (aliphatic hydrocarbons with 1-4carbons), styrene-butadiene-(metha)acrylate esters (aliphatichydrocarbons with 1-4 carbons), styrene-anhydrous maleate, andstyrene-anhydrous itaconic acid. Of them preferred are polystyrene,styrene-butadiene, styrene-acrylonitrile, styrene-butadiene, andstyrene-anhydrous maleic acid.

Other polymers may include polyphenylene ether, polycarbonate,polyphenylene sulfide, and polyethyleneterephthalate, and of thempreferably polyphenylene ether and polycarbonate.

The anionic polymer aggregating agent can be prepared by recyclingpolystyrene resins which are mass-produced as a general-purpose resinmaterial for many products, and hence can incorporate convenientlysulfonates of polystyrene resins.

<Cationic polymer aggregating agents>

Preferred are polymers of the quaternary compound ofdialkylaminoalkyl(metha)acrylate (for example, with methyl chloride,benzyl chloride, etc.) or its salts (inorganic salts such aschlorinates, sulfates, etc., and organic salts such as acetates, etc.)or their compolymers with (metha)acrylamide.

For example, polymers of the quaternary compound ofdimethylaminoetheracrylate with methylchloride, or their copolymers withacrylamide are preferred.

Polymers of the quaternary compound ofdialkylaminoalkyl(metha)acrylamide or their acidic salts, or theircopolymers with (metha)acrylamide are preferred.

For example, copolymers of the quaternary compound ofdimethylaminopropylacrylamide incorporating methylchloride, withacrylamide are preferred.

Compounds which are produced after polyacrylamide has been made to havea cationic activity, and they include, for example, those that areproduced after polyacrylamide has undergone Mannig's degeneration orHoffman's decomposition.

Compounds which are produced after epihalohydrine-amine has beencondensed, and they include, for example, a polymerized condensatebetween epihalohydrine and alkylene diamine with 2-8 carbons.

Polydimethyldiallylammonium chloride

Condensates of dicyandiamide, and they include, for example, formalincondensates of dicyandiamide and ammonium chloride.

Polyethylene imine

Polyvinylimizazoline

Acid salts of chitosan

The cationic polymer aggregating agent preferably includes polymers ofthe quaternary compounds of dialkylaminoalkyl (metha)acrylate or theiracid salts, and their copolymers with (metha)acrylamide, polymers of thequaternary compounds of dialkylaminoalkyl(metha)acrylamide or their acidsalts, or their copolymers with (metha)acrylamide, and acid salts ofchitosan.

A plurality of polymer aggregating agents with the same ionic type maybe combined, or a plurality of polymer aggregating agents with acombination of anionic and non-ionic activities, or with a cationic andnon-ionic combination may be used.

The polystyrene resin may be chosen from new materials (virgin material)specially prepared for the production of polymer electrolytes of thisinvention, or from wastes (waste materials) from plants, shops andhouseholds. Or, a combination of virgin and waste materials may be used.As seen from above, this invention can recycle polystyrene which hasbeen mass-produced as a general-purpose resin, and hence is verybeneficial for the protection of global environment from artificialpollutants. From this point of view, it is desirable for this inventionto adopt waste materials as a source of polystyrene resins rather thanvirgin materials. Since many of waste polystyrene resin materialscontain carbon black, and will provide, when the polystyrene resin hasbeen converted to a sulfonate, an aggregating agent containing asufficient amount of carbon black.

For a polystyrene resin to be sulfonated, it is only necessary todissolve or disperse the polystyrene resin in an organic solvent, and toadd a sulfonating agent to the solution. The solution, aftersulfonation, is neutralized through reaction with a basic compound, andthe solvent is removed by fractional distillation or by evaporation. Thesolvent preferably includes aliphatic halogenated hydrocarbons with 1-4carbons represented by 1,2-dichlorohexane, and aliphatic, cycliccompounds represented by cyclohexane.

This invention may recycle polymer electrolytes which contain asulfonated styrene polymer as a principal ingredient, and whosemolecular weight is 150,000 to 600,000.

The polystyrene resin used for this purpose may be chosen from newmaterials (virgin material) specially prepared for the production ofpolymer electrolytes of this invention, or from wastes (waste materials)from plants, shops and households. Or, a combination of virgin and wastematerials may be used. This invention can recycle polystyrene which hasbeen mass-produced as a general-purpose resin, and hence is verybeneficial for the protection of global environment from artificialpollutants. From this point of view, it is desirable for this inventionto adopt waste materials as a source of polystyrene rather than virginmaterials.

The above-described polymer aggregating agent can be obtained byallowing specified amounts of styrene polymer, sulfonating agent andsolvent to mix and undergo sulfonating reaction.

For this sulfonating reaction, addition of the styrene polymer ispreferably set to 0.1-30 wt %, or more preferably to 0.5-20 wt %. If thestyrene polymer is allowed to have a concentration lower than aboverange, it will be difficult to introduce sulfone group into the styrenepolymer. On the contrary, if the styrene polymer is adjusted to have aconcentration exceeding above range, gels will readily develop duringsulfonation, or a large fraction of polymer will remain unreacted.

Sulfonation reaction is preferably allowed to proceed at 0-100° C., ormore preferably at 15-80° C. If the reaction temperature is set belowthis range, sulfonation will hardly take place, and the yield of polymeraggregating agent will be reduced.

Further, the sulfonating reaction is allowed to take 10 minute to 10hours, more preferably 30 minutes to 5 hours (the time required fordropwise addition of the sulfonating agent is not included).

The solution, after having completed sulfonation in the manner asdescribed above, has sulfone group neutralized by the addition of aneutralizing agent, and is removed of its solvent through evaporation,to produce the target polymer aggregating agent.

The neutralizing agent may include oxides, hydroxides, carbonates,acetates, sulfates and phosphates of basic compounds such as alkalimetals (sodium, lithium, potassium, etc.) and of alkali earth metals(magnesium, calcium, etc.), ammonia, and various (primary to tertiaryalkyl) amine compounds. The neutralizing agent may be slowly added as asolid or an aqueous solution to the reaction system, to neutralizesulfone group introduced into the styrene polymer. Removal of thesolvent may take place through fractional distillation or evaporation.

The thus-obtained polymer aggregating agent must have a molecular weightof 150,000 to 600,000, or more preferably 200,000 to 500,000. Thepolymer aggregating agent of which the sulfonated styrene polymer has amolecular weight less than 150,000 will lose the activity to aggregatesuspended particles in a suspension, and rather disperse those suspendedmatters into the solvent. On the contrary, if the sulfonated styrenepolymer has a molecular weight of 600,000 or more, it will causesuspended particles to aggregate into coarse masses, not being able topurify water sufficiently, and the resulting cake will contain too muchwater.

For this polymer aggregating agent, 40 mol % or more, or preferably 50mol % or more sulfone group is introduced into the styrene polymer. Thepolymer aggregating agent, of which the styrene polymer contains 40 mol% or less sulfone group, will become less soluble to water, and thusgreatly lose the aggregating activity towards suspended matters in asuspension.

As discussed above, for the desired amount of sulfone group to beintroduced into the styrene polymer to produce a proper polymeraggregating agent, the styrene unit preferably occupies 60 mol %, ormore preferably 80 mol % or more of the styrene polymer. If the fractionof styrene unit in the styrene polymer were less than 60 mol %, it wouldbe difficult to obtain a polymer aggregating agent in which the desiredamount of sulfone group can be introduced through sulfonation.

The thus-obtained polymer aggregating agent may be used in combinationwith another aggregating agent consisting of acrylamide polymer withnon-ionic and/or anionic activity, for the treatment of waste water. Theagent in question may be used in combination with another aggregatingagent with cationic activity as well.

Any one of non-ionic, anionic, or cationic polymer aggregating agentsthat have been cited above may be used.

The polymer aggregating agent, when used in combination with anotheraggregating agent, may be combined with the latter prior to use, or maybe added separately during use. Particularly, when it is used incombination with a cationic polymer aggregating agent, it is preferablyadded separately during use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Polymer Electrolyte Containing an Inorganic Substance

A resin was prepared by grinding following substances with a millingmachine.

(a) Polystyrene . . . Aldrich, molecular weight (Mw)=280,000 (free frominorganic pigments)

(b) High impact polystyrene . . . housing material for VHS cassettetapes (containing 1 wt % carbon black)

(c) High impact polystyrene: alloy with polyphenyleneether . . . housingmaterial of facsimile machines (containing 2 wt % titanium oxide)

(d) Polystyrene: alloy with polyphenyleneether . . . housing material ofCD-ROM drives (containing 2 wt % carbon black)

EXAMPLE 1

Sixty gram of polystyrene (a) was dissolved in 540 g of1,2-dichloroethane, to which was added 0.5 g of carbon black (a standardproduct for coloration, HCC type, having an average particle size of9-14 nm). The mixture was heated to 50° C., to which was dropwise added77 g of 60% fuming sulfuric acid over 30 minutes.

A slurry product developed in the reaction system, but there was no geladherence on the wall of the reaction vessel throughout the reactionprocess.

After dropwise addition, for further 30 minutes, the mixture was kept atthe same temperature for sulfonation, and while the reaction proceededan aqueous solution of sodium hydroxide was added for neutralization.Then, the mixture was heated to remove 1,2-dichloroethane throughevaporation, and the residue was dissolved in water, which was thenadjusted with sodium hydroxide to give pH 8. This procedure gave a 20 wt% aqueous solution of the polymer electrolyte.

The thus obtained aqueous solution of the polymer electrolyte wasallowed to stand at room temperature for one month, and still held agood homogenous dispersibility.

EXAMPLE 2

A solution was produced after 6.93 g of high impact polystyrene (b) wasdissolved in 63 g of 1,2-dichloroethane. The first solution and 9.33 gof 60% fuming sulfuric acid were simultaneously added dropwise over 60minutes to a solution which was produced after 2.44 g oftriethylphosphate had been added to 70 g of 1,2-dichloroethane. Duringdropwise addition, the reaction system was controlled to be in the rangeof 20-25° C.

Carbon black contained in the high impact polystyrene (b) dispersedevenly in the reaction system, and produced stable, slurry compoundswith the progression of sulfonation. In this example either, there wasno adherence of gel substances to the wall of the reaction vessel.

After dropwise addition, for further 30 minutes, the mixture was kept atthe same temperature for sulfonation, and, while the reaction proceeded,an aqueous solution of sodium hydroxide was added for neutralization.Then, the mixture was heated to remove 1,2-dichloroethane throughevaporation, and the residue was dissolved in water to give a 20 wt %aqueous solution of the polymer electrolyte.

The thus obtained aqueous solution of the polymer electrolyte wasallowed to stand at room temperature for one month, and still held agood homogenous dispersibility.

EXAMPLE 3

A solution produced after 0.6 g of triethyl phosphate had been added to70 g of 1,2-dichloroethane, while being kept at 20-25° C., was added to0.27 g of anhydrous sulfuric acid. A solution produced after 7.0 g ofalloy (c) of high impact polystyrene-polyphenylene ether had beendissolved in 63 g of 1,2-dichloroethane, and 5.4 g of anhydrous sulfuricacid, while being kept at the same temperature, were simultaneouslyadded dropwise over 60 minutes to the foregoing mixture.

Titanium oxide contained in the high impact polystyrene (c) dispersedevenly in the reaction system, and produced stable, slurry compoundswith the progression of sulfonation. In this example either, there wasno adherence of gel substances to the wall of the reaction vessel.

After dropwise addition, 32 g of an aqueous solution containing 3.0 g ofsodium hydroxide was slowly added with stirring to the reaction systemfor neutralization. Then, the mixture was heated to remove the solventthrough evaporation, the residue was dissolved in water, and the aqueoussolution was adjusted by the addition of sodium hydroxide to give pH 8.This procedure produced an aqueous solution containing 30 wt % polymerelectrolyte.

The thus obtained aqueous solution of the polymer electrolyte wasallowed to stand at room temperature for one month, and still held agood homogenous dispersibility.

EXAMPLE 4

The same procedure was employed as in Example 3 except that an alloy (d)of polystyrene-polyphenylene ether was used instead of the alloy of highimpact polystyrene-polyphenylene ether (c), to produce an aqueoussolution of polymer electrolyte.

In this case too, carbon black contained in the alloy (d) ofpolystyrene-polyphenylene ether dispersed evenly in the reaction system,and produced stable, slurry compounds with the progression ofsulfonation. In this example either, there was no adherence of gelsubstances to the wall of the reaction vessel.

The thus obtained aqueous solution of the polymer electrolyte wasallowed to stand at room temperature for one month, and still held agood homogenous dispersibility.

Comparative Example 1

The same procedure was employed as in Example 1 except that carbon blackwas not added, to produce an aqueous solution of polymer electrolyte.

In this Comparative Example, about 10 minutes after dropwise addition offuming sulfuric acid, a solid mass of gel substances developed in thereaction system, and, on completion of the dropwise addition, the gelsubstances adhered to the wall of the reaction vessel. In addition,these gel substances remained insoluble to water or alkaline aqueoussolutions.

Evaluation of Performance

Comparison of Example 1 and Comparative Example 1 showed that thepresence of carbon black inhibits the development of by-productsinsoluble to water while polystyrene is undergoing sulfonation.

Example 2 further revealed that waste materials derived from usedpolystyrene resins can provide a good yield of aqueous solution ofpolymer electrolyte, and that used polystyrene resins already contain asufficient amount of carbon black.

Further, results from Examples 3 and 4 demonstrated that an alloy ofpolystyrene resin with another polymer can provide an aqueous solutionof polymer electrolyte as good as that provided by a polystyrene resinalone.

Polymer Aggregating Agent Containing Carbon Black

EXAMPLE 5

Twenty-five wt % aqueous solution of polystyrene sodium sulfate wasprepared as a polymer aggregating agent, to which was added carbon black(for coloration of plastics, HCC type, having an average particle sizeof 9-14 nm) to 0.1 wt %, and allowed to disperse. This solution was madethe sample of Example 5.

EXAMPLE 6

High impact polystyrene (used housing materials for VHS cassette tapes,containing 2 wt % carbon black) was dissolved in 1,2-dichloroethane, towhich was added dropwise anhydrous sulfuric acid at 20-25° C. forsulfonation. Then an aqueous solution of sodium hydroxide having thesame molar concentration with the anhydrous sulfuric acid was added forneutralization, and the solvent was removed by evaporation, to producean aqueous solution of polymer aggregating agent containing 20 wt %polymer. This solution also contained 0.2 wt % carbon black. This wasmade the sample of Example 6.

EXAMPLE 7

An aqueous solution of 0.05 wt % partially hydrolyzed polyacrylamide wasprepared as a polymer aggregating agent, to which was added carbon blacksimilar to that in Example 5 to 0.005 wt %, and was allowed to disperse.This was made the sample of Example 7.

EXAMPLE 8

The sample of Example 5 and that of Example 7 were mixed at a volumeratio of 1:1. This was made the sample of Example 8.

EXAMPLE 9

A 0.2 wt % of aqueous solution of the quaternary compound ofdimethylaminoethylmethacrylate with methylchloride was prepared, towhich was added carbon black similar to that in Example 5, to 0.01 wt %,and allowed to disperse. This was made the sample of Example 9.

Comparative Example 2

The same aqueous solution as in Example 5 was prepared except thatcarbon black was not added. Thus, an aqueous solution of 25 wt %polystyrene sodium sulfonate was made the sample of Comparative Example2.

Comparative Example 3

The same aqueous solution as in Example 7 was prepared except thatcarbon black was not added. Thus, an aqueous solution of 0.05 wt %partially hydrolyzed polyacrylamide was made the sample of ComparativeExample 3.

Comparative Example 4

The same aqueous solution as in Example 8 was prepared except that itdid not contain carbon black. Thus, a 1:1 (in a volume ratio) mixture ofthe sample of Comparative Example 2 and that of Comparative Example 3was made the sample of Comparative Example 4.

Comparative Example 5

The same aqueous solution as in Example 9 was prepared except thatcarbon black was not added. Thus, an aqueous solution of 0.2 wt %polymer of the quaternary compound of dimethylaminoethylmethacrylatewith methylchloride was made the sample of Comparative Example 5.

Evaluation of Performance

The above samples were submitted to following tests to evaluate theirperformance of treating waste water.

Firstly, waste water discharged from an electronic parts manufacturingplant (pH 3.2, having an SS concentration of 0.5 wt %, and having a CODconcentration of 50 ppm) was sampled, to which was added 500 ppm ofaluminum sulfate. The resulting suspension was made a test substratewith which to evaluate the performance of the samples. Hundredmilliliter aliquots (100 ml) of the test substrate were placed in 200 mlvolumetric cylinders with a cap. The samples from Examples 5-8 andComparative Examples 2-4 were separately added to the test substrate togive a concentration of 5.0 ppm. Immediately thereafter the volumetriccylinder was stirred by being placed upside down and returned repeatedlyten times, and allowed to stand. While it was left to stand, thesedimentation rate of suspended particles, the turbidity of the filtrateafter sedimentation, and the COD of the supernatant were determined. Theresults are shown in Table

                  TABLE 1                                                         ______________________________________                                                  Sedimentation Turbidity                                                                              COD                                             rate (m/hour) (ppm) (ppm)                                                  ______________________________________                                        Example 5 23            40       11                                             Example 6 22 35 10                                                            Example 7 25 63 14                                                            Example 8 25 38 11                                                            Comparative 22 73 17                                                          Example 2                                                                     Comparative 20 80 23                                                          Example 3                                                                     Comparative 24 70 18                                                          Example 4                                                                   ______________________________________                                    

From Table 1 it is obvious that all the samples from Example 5-8 have abasic property as a polymer aggregating agent, and are especially moreactive in reducing the turbidity of the filtrate after sedimentationthan the samples from Comparative Examples 2-4 which contained no carbonblack.

Above results demonstrate that a polymer aggregating agent, whencombined with carbon black, becomes greatly improved in its treatmentactivity towards waste water, particularly in its purifying activitytowards suspensions. It was also found that the polymer aggregatingagent may include polyethylene sodium sulfonate and partially hydrolyzedpolyacrylamide, and that polystyrene sodium sulfonate may includematerials prepared from used polystyrene resins.

Mixed slurry discharged from a sewage treatment plant (pH 6.8, having anSS concentration of 2.8 wt %, and a COD concentration of 250 ppm) wassample to be used as a test substrate with which to evaluate theperformance of the samples. The samples from Example 9 and ComparativeExample 5 were separately put into jars containing the test substratewhile the substrate being stirred, at a rate of 0.5 wt % for every SSpercent. The mixture was left to stand, and the sedimentation rate,turbidity and COD of the supernatant were determined. The results areshown in Table 2.

As a reference, 200 ppm of carbon black was added to the test substrate,and the sample of Comparative Example 5 was added at 0.5 wt % for everySS percent, and the same measurement was undertaken for the resultingmixture. This case was taken as Example 10, and the results are shownunder the heading of Table

                  TABLE 2                                                         ______________________________________                                                  Sedimentation Turbidity                                                                              COD                                             rate (m/hour) (ppm) (ppm)                                                  ______________________________________                                        Example 9 40            21       18                                             Comparative 35 49 34                                                          Example 5                                                                     Example 10 38 28 23                                                         ______________________________________                                    

From Table 2 the following finding was obtained. When a mixtureincluding carbon black and an aqueous solution of polymer aggregatingagent was added to the test substrate (Example 9), or when the aqueoussolution of polymer aggregating agent was added following the additionof carbon black (Example 10), the sewage treatment activity was moreenhanced, or more specifically the test substrate became moreeffectively purified than was possible with the single use of theaqueous solution of polymer aggregating agent not being supplementedwith carbon black (Comparative Example 5). From this, it was indicatedthat a polymer aggregating agent when supplied with carbon black,whether the supply occurs prior to or during treatment, will be greatlyimproved in its treatment activity towards waste water.

Polymer Aggregating Agents Including a Styrene Polymer of aComparatively Large Molecular Weight

EXAMPLE 11

The polymer aggregating agent of Example 11 included polystyrene sodiumsulfonate (Scientific Polymers Co.) or a sulfonated styrene polymer. Inthis example, polystyrene sodium sulfonate was adjusted to have amolecular weight of 17.5×10⁴.

EXAMPLE 12

The polymer aggregating agent of Example 12 included polystyrene sodiumsulfonate (Scientific Polymers Co.) whose molecular weight was 50.0×10⁴.

EXAMPLE 13

The polymer aggregating agent of Example 13 was prepared as follows.

High impact polystyrene (used housing materials for VHS cassette tapes,having a molecular weight of Mw=17.7×10⁴) was dissolved in1,2-dichloroethane, to which was added dropwise anhydrous sulfuric acidat 20-25° C. for sulfonation. Then an aqueous solution of sodiumhydroxide having the same molar concentration with the anhydroussulfuric acid was added for neutralization, and the solvent was removedby evaporation, to produce an aqueous solution of polymer aggregatingagent. This solution was made the sample of Example 13.

The polymer aggregating agent of Example 13 contains polystyrene sodiumsulfonate having a molecular weight of 350,000.

EXAMPLE 14

The polymer aggregating agent of Example 14 was obtained in the samemanner as in Example 13 except that used housing materials of TV wereused as high impact polystyrene (Mw=22.4×10⁴). The polymer aggregatingagent of this example contained polystyrene sodium sulfonate whosemolecular weight was 450,000.

EXAMPLE 15

The polymer aggregating agent of Example 15 was obtained after ahydrolyzed product of the polyacrylamide portion of an anionic polymeraggregating agent had been added to the polymer aggregating agent ofExample 13 at a weight ratio of 1:1.

EXAMPLE 16

The polymer aggregating agent of Example 16 was obtained after thequaternary compound of dimethylaminoethylacrylate with methylchloride asa cationic polymer aggregating agent and the polymer aggregating agentof Example 13 had been introduced into a test substrate in the mannerdescribed below for mixture.

EXAMPLE 17

The polymer aggregating agent of Example 17 was obtained after thequaternary compound of dimethylaminoethylacrylate with methylchloride asa cationic polymer aggregating agent and the polymer aggregating agentof Example 15 had been introduced into a test substrate in the mannerdescribed below for mixture.

Comparative Example 6

The polymer aggregating agent of Comparative Example 6 consisted ofpolystyrene sodium sulfonate (Scientific Polymers Co.) having amolecular weight of 7.0×10⁴.

Comparative Example 7

The polymer aggregating agent of Comparative Example 7 consisted ofpolystyrene sodium sulfonate (Scientific Polymers Co.) having amolecular weight of 120×10⁴.

Comparative Example 8

The polymer aggregating agent of Comparative Example 8 was obtainedafter the quaternary compound of dimethylaminoethylacrylate withmethylchloride as a cationic polymer aggregating agent and the polymeraggregating agent of Comparative Example 6 had been introduced into atest substrate in the manner described below for mixture.

Comparative Example 9

The polymer aggregating agent of Example 14 was obtained after thequaternary compound of dimethylaminoethylacrylate with methylchloride asa cationic polymer aggregating agent and the polymer aggregating agentof Comparative Example 7 had been introduced into a test substrate inthe manner described below for mixture.

Examples 11 to 17 and Comparative Examples 6 to 9 prepared as above wereexamined for their treatment activity towards waste water as follows.

Determination of Activity

Waste water discharged from an electronic parts manufacturing plant (pH4.8, and having an SS concentration of 1.2 wt %) was sampled, to whichwas added 500 ppm of aluminum sulfate. The resulting suspension was madea test substrate with which to evaluate the performance of the samples.Hundred milliliter aliquots (100 ml) of the test substrate were placedin 200 ml volumetric cylinders with a cap. The samples from Examples11-15 and Comparative Examples 6-7 were separately added to the testsubstrate to give a concentration of 10.0 ppm. Immediately thereafterthe volumetric cylinder was stirred by being turned upside down andreturned repeatedly ten times, and allowed to stand. While it was leftto stand, the sedimentation rate of suspended particles, the turbidityof the filtrate after sedimentation, and the water content of residualsolid (cake) were determined. The results are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                                  Sedimentation                                                                              Turbidity                                                                              Water content                                    rate (m/hour) (ppm) of cake (ppm)                                          ______________________________________                                        Example 11                                                                              20           24       70                                              Example 12 22 28 72                                                           Example 13 20 22 73                                                           Example 14 22 20 71                                                           Example 15 25 20 70                                                           Comparative 1 -- --                                                           Example 6                                                                     Comparative 21 85 76                                                          Example 7                                                                   ______________________________________                                    

From Table 3 it is obvious that all the samples from Examples 11-15 havea basic property as a polymer aggregating agent, and are far more activein reducing the turbidity of the filtrate after sedimentation than thesample from Comparative Example 7 whose molecular weight is outside therange of 150,000-600,000. This result demonstrates that a polymeraggregating agent which contains a sulfonated styrene polymer as aprincipal ingredient and has a molecular weight in the range of150,000-600,000 is greatly improved in its treatment activity towardswaste water, especially in its purification of suspensions.

It was also found that the samples of Examples 11-15 are more effectivein reducing the water content of dehydrated cakes than those fromComparative Examples 6 and 7 or the polymer aggregating agents with amolecular weight being outside the range of 150,000-600,000. This resultdemonstrates that a polymer aggregating agent with a molecular weight inthe range of 150,000-600,000 is greatly improved in its treatmentactivity towards waste water, especially in its recovery of purifiedwater from sewage which will be served for reuse.

It was further ascertained that the polymer aggregating agent mayinclude partially hydrolyzed polyacrylamide, and that polystyrene sodiumsulfonate may include materials prepared from used polystyrene resins.

Mixed slurry discharged from a sewage treatment plant (pH 6.6, andhaving an SS concentration of 2.8 wt %) was sampled to be used as a testsubstrate with which to evaluate the performance of the samples. Thesamples from Examples 16 and 17, and Comparative Examples 8 and 9 wereseparately put into jars containing the test substrate while thesubstrate being stirred. The added amount was so adjusted as to give 0.6wt % quaternary compound of dimethylaminoethylacrylate withmethylchloride for every percent of SS. Then, polystyrene sodiumsulfonate specific to Examples 16 and 17 and to Comparative Examples 8and 9 was added at a ratio of 0.15 wt % to every percent of SS. Themixture, after being stirred, was left to stand, and the sedimentationrate, turbidity of the filtrate after sedimentation, and the watercontent of cakes were determined. The results are shown in Table 4.

                  TABLE 4                                                         ______________________________________                                                  Sedimentation                                                                              Turbidity                                                                              Water content                                    rate (m/hour) (ppm) of cake (ppm)                                          ______________________________________                                        Example 16                                                                              38           28       72                                              Example 17 40 25 70                                                           Comparative 20 61 76                                                          Example 8                                                                     Comparative 38 56 78                                                          Example 9                                                                   ______________________________________                                    

From Table 4 it is obvious that, as with the case for sewage from anelectronic parts manufacturing plant, the use of a polymer aggregatingagent containing a sulfonated styrene polymer as a principal ingredientand having a molecular weight of 150,000-600,000 is far more active inreducing the turbidity of the filtrate after sedimentation, and inreducing the water content of cake produced after dehydration of thesediment than the samples from Comparative Examples 8 and 9.

It was further ascertained that the polymer aggregating agent mayinclude, in addition, the quaternary compound ofdimethylaminoethylacrylate with methylchloride, and that polystyrenesodium sulfonate may include materials prepared from used polystyreneresins.

What is claimed is:
 1. A method of producing a polymer electrolytecomprising the step of: sulfonating a polystyrene resin in the presenceof an inorganic pigment to provide a water-soluble polymer electrolyte.2. A method of producing a polymer electrolyte as defined in claim 1wherein the inorganic pigment is added prior to sulfonation.
 3. A methodof producing a polymer electrolyte as defined in claim 1 wherein theinorganic pigment is present in the polystyrene resin starting material.4. A method of producing a polymer electrolyte as defined in claim 1wherein the polystyrene resin is derived from a waste material.
 5. Amethod of producing a polymer electrolyte as defined in claim 1 furthercomprising the step of dissolving the polystyrene resin in a solventprior to sulfonation.
 6. A method of producing a polymer electrolyte asdefined in claim 1 wherein the inorganic pigment is carbon black ortitanium oxide.
 7. A method of producing a polymer electrolyte asdescribed in claim 1, wherein the organic pigment is carbon black.
 8. Apolymer aggregating agent comprising a sulfonate of polystyrene resinand carbon black, and wherein said sulfonate of polystyrene resin has amolecular weight of from 200,000 to about 600,000.
 9. A polymeraggregating agent as defined in claim 8 wherein the styrene polymercontains, through sulfonation, 40 mol % or more sulfone group withrespect to the total weight of monomer units.
 10. A polymer aggregatingagent as defined in claim 8 wherein the styrene polymer is derived froma waste material.
 11. A polymer aggregating agent comprising a sulfonateof a polystyrene resin and carbon black, and further comprising anon-ionic or anionic acrylamide resin.
 12. A polymer aggregating agentcomprising a sulfonate of a polystyrene resin and carbon black, andfurther comprising a cationic resin.